As is evidenced by what people are actually buying right now, it's the other way around. The consumers on board with this are used to micro transactions for minuscule additions to their games. Pretty swords and armours are the way to go if you wish to make a buck behind the pay wall.
Big quality projects require many more then just one person to make. Depending on what you can do yourself, limited by skill and/or time. What's needed: voice acting, building of exterior/interior cells, modelling, texturing, scripting, scenario writing, proof reading, Q&A, legal counselling (<- every business requires this), etc, etc.
A project like Falskaar got huge help and support from the comunity when asked, resources and time were shared for free. When a mod is intended for the pay wall, it's far less likely anyone will be willing to chime in and help only for kudos in the credits section. Those people will more then not require financial compensation for their work, just like the mod will be requiring financial compensation. With the relatively limited amount of revenue that is to be expected versus the relative cost involved, a sustainable income from projects like that is far from to be expected.
I firmly reject the notion we'll get to see more mods like Falskaar, or bigger projects then Falskaar, just because there's now money involved. I firmly believe that those who are interested in cashing behind the pay wall are much more likely to go for the quick and easy way of things. Churn out some models and textures, slap it into a micro transaction, reek in the cash.
And besides all that. If the intention is to make 10x bigger projects then Falskaar. Go get a licence for one of the many excellent cheap engines out there and go build and release a game on Greenlight and/or early access. If it's any good it's far more likely to gain any attention and potentially can generate way more income then what a "mere mod" can do.